DESCRIPTION: (Investigator's abstract): This research project processes to develop a commercially viable instrument to accurately and reliably measure discomfort glare relevant to problems reported by certain workers and patients. Complaints of glare abound with VDT operators and is an important issue in occupational medicine. Certain refractive surgical procedures and newer intraocular implants have created glare problems, some of which appear to be associated with discomfort glare. These glare issues are important to visual comfort and performance. A contemporary understanding and measurement of discomfort glare is crucial. The discomfort glare tester (DGT) proposed will provide an occupational and clinical measure of discomfort glare that is not available. The novel aspect of the DGT is that it incorporates tests that measure discomfort glare independently of disability glare. As examples, the DGT will provide a measure of discomfort glare which relates to the light from luminaries and vehicle headlights. Furthermore, the DGT will measure individual discomfort glare sensitivity useful for the prescription of tinted determine if the test system is valid (2) measure the reliability of the DGT (3) determine the specificity and sensitivity of the system. Phase II of this research will involve the development of a commercially viable discomfort glare tester for use in large population data collection applicable to occupational and clinical problem.